You will have seen the pros wearing Blood Glucose Monitors in Kona last year. What are they? How do they work? And do you, as an age grouper triathlete need to monitor your blood glucose to improve your performance?
Continuous glucose monitoring (CGM) devices typically consist of a small pager-like monitoring device that receives a signal from a sensor inserted into the subcutaneous layer. With their 1 - 5 minute measurement interval, they allow blood glucose concentration (BG) dynamics to be captured.
These devices are primarily designed for the use in type 1 and type 2 diabetic individuals to aid Blood Glucose regulation and are well studied in this cohort.
In particular, there is ongoing research to improve carbohydrate delivery and oxidation, resulting in less accumulation of carbohydrate in the gastrointestinal track to decrease gastrointestinal problems during prolonged exercise.
The CGM data could aid optimal carbohydrate delivery by allowing an athlete to know the best time and the amount of carbohydrate to consume. Also , the optimal timing and amount of carbohydrate delivery has the potential to increase glycogen storage speeding athlete recovery and providing additional energy for racing and training.
However, the accuracy and performance of CGM devices in active, trained athletes must be evaluated.
It’s measuring BG – but for CHO to be there you need to digest it first. Gut rate limiter.
Gives you info about BGL – but it doesn’t tell you about what CHO ox is happening at the muscle. It doesn’t tell you how much glycogen you have stored, so it’s not giving you the full picture.
While great for Type 1 Diabetics and useful for the Elites (to help really dial things in) for most age groupers this would come in the category of a gadget or shiny new object.
I’m big on foundations first. Walk before you run. There’s lots you should do first before forking out for a patch.
Nothing to see here folks. High carb products are, more often than not, simply bigger packaging, for example:
Precision Hydration PH 90g gel = 153 g serving, whereas PH 30g gel = 50g serving
Maurten 160 mix = 40g vs 320 mix = 80g
There’s a trend too with glucose fructose ratios - have traditionally been a ratio 1:2 but some products now at 1:0.8.
1:2 ratio - great if trying to fuel it around 60 to 90 grams of carbohydrate an hour.
1:0.8 ratio - only if looking at pushing that beyond that - to 90 to 100/ 110/ 120 grams of carbohydrate per hour.
Research is progressing in this area. Previously the max was 60g/hr, then moved to 90 g/hr and now we’re seeing research exploring higher intakes of 120g/hr. But for the average age group triathlete – not necessary and difficult for the gut to manage.
Tip: you don’t HAVE to follow the guidelines on a packet – dial in your fuelling and strategy based on you and what you need.
The exception to this would be the Maurten Hydrogel – follow their instructions to avoid gastric emptying!!
I did an episode on why probably aiming for 120 grams of carbohydrate an hour for a general age grouper is likely a mistake. Take a listen - I walk you through some of the research in this space. And why it may not be so useful for an everyday athlete.
Gut training is something endurance athletes need to be doing if you want to increase your fuelling but no point putting that amount of carbohydrate into your gut, if it's not going anywhere - that's only going to end badly, the longer you exercise.
Our gut is the rate limiter - we can throw 200-300 grams of carbohydrate into our stomach, but it just isn't going to digest and absorb and move across the intestinal wall into our bloodstream.
There has been a growing trend around body composition and the need to NOT be the leanest, lightest body that you can be.
At 2000 Sydney Olympic Games elite athletes were very lean and light. But now a push to put on more muscle so we have more strength - we're stronger and we have more power.
Increase weight - but muscle weight, not fat weight.
So strong, not skinny - like Blummenfelt, as an example.
Don’t be carb phobic, don’t under fuel.
Eat strategically, fuel better, put on muscle, get strength and power, so you can train and race harder.
There is a trend that sees people obsessed with the low carb high fat diet that is Keto.
I have an expert in this space, Louise Burke. recording a podcast with me shortly so keep an eye out for that.
If you are a slower athlete, a big diesel engine, you're happy to go at very aerobic intensity for a long period of time and you don't want any speed or intensity, then it could potentially work for you. But as soon as you want to go faster, and the intensity rises, or potentially you do a very hilly course where your heart rate is going to spike, then the low carb high fat or keto methodology may not be the best fit for you.
I recommend strategic periodisation of your carbohydrate.
Exploring the merits of following a keto, vegetarian, vegan or plant based diet is a whole podcast episode in itself!
This trend surfaced a few years ago. Paleo to Vegan, the Netflix documentary, saw people that went from a diet of eating T-bone the size of my quad switching to a plant-based diet! No wonder they saw an improvement!
Vegan - excludes all animal products - fish, eggs, honey (and even leather products
Vegetarian - may include eggs, dairy, fish etc.
Plant-Based - eat a diet based purely on plants.
Whichever way you choose to eat, my advice to you is just make sure you're still ticking all the right boxes for what you need. So if you plan on going vegan or plan on making a change to your diet like that, you just need to understand - what are the things that you will then be missing? And how do you replace that effectively with the plant based alternatives? E.g. Protein and key nutrients that are important in endurance sport - Iron, Zinc, Calcium, B12, creatine (lower stores).
I’d not recommend a quick change - understand how to meet needs before making a rapid change.
Lots of athletes would benefit from eating more plant-based foods - without the need to put rules around diet. I recommend triathletes look to improve their overall diet quality - higher antioxidants - without excluding animal based food.